The Neuropathology (NP) Core performs diagnostic evaluations and quantitative analyses on brain tissue collected at autopsy of participants in the Mayo Alzheimer Disease Research Center (ADRC). The NP Core provides support to research projects of the ADRC and to other center affiliated investigators. The neuropathologic and genetic data generated by the NP Core is communicated to the Biostatistics and Data Management Core and to the National Alzheimer Coordinating Center. The approach for the NP Core is to: 1. Perform brain autopsies on participants of the Mayo ADRC in a timely fashion and according to protocol. 2. Provide neuropathologic evaluations and collect neuropathologic data using standardized methods for gross dissection and neurohistology. a. Cooperate with Mayo Clinic research neuroradiology in acquisition of post-mortem MRI scans of brains. b. Dissect brains according to a standardized protocol and photograph all sections. Score the severity of cerebrovascular pathology, and measure and sample macroscopic cerebrovascular lesions. c. Use histological methods, including silver stains, thioflavin S fluorescent microscopy and immunohistochemistry for tau and A?, to collect standardized pathologic data on all cases. d. Perform immunostaining with antibodies to ?-synuclein on all cases. In cases with Lewy bodies, assign a diagnosis according to the criteria of the Consortium for Dementia with Lewy Bodies. e. Perform immunostaining with antibodies to TDP-43 on all cases and when positive on the screening section, subtype and map the distribution of TDP-43 pathology. f. Arrive at a consensus on clinicopathologic diagnoses at videoconferences held twice a month. g. Provide neuropathological data to the Biostatistics Core and NACC. 3. Store brain tissue and other autopsy-derived materials (e.g., DNA) and provide clinically and pathologically well-characterized tissue samples, DNA or data to ADRC research projects and pilot projects at Mayo Clinic as well as qualified outside investigators. 4. Assist ADRC research projects by providing neuropathologic expertise, tissue or histopathologic services. a. Assist in neuropathologic classification of cases included in the MRI studies of Project 1, which aims to develop an image based diagnostic software program that predicts the underlying pathology. b. Provide autopsy tissue samples of brains of subjects with a range of neurofibrillary pathology in AD and other tauopathies to Project 2 and assist in tissue processing and histologic studies of mouse models. c. Provide brain tissue samples to Project 3 as well as data on cerebral amyloid angiopathy (CAA) with respect to type, distribution, and severity; as well as data on burden of cerebrovascular pathology. 5. Provide genetic screening for ADRC sample sets with respect to existing and newly discovered genes.